Radiation therapy in clinically node positive HER2 positive breast cancer after primary systemic therapy and breast conserving surgery: pooled analysis of TRYPHAENA and NeoSphere trials
Menée à l'aide des données de 2 essais randomisés de phase II portant sur 90 patientes atteintes d'un cancer du sein HER2+ avec envahissement ganglionnaire et ayant reçu un traitement systémique suivi d'une chirurgie conservatrice du sein, cette étude évalue l'intérêt, du point de vue de la survie sans récidive, d'une irradiation des aires ganglionnaires
Background: The benefit of regional nodal irradiation (RNI) following modern primary systemic therapy (PST) in HER2-positive breast cancer (HER2 + BC) remains under investigation. The current study evaluates RNI practice patterns and outcomes based on the pathological response to PST in clinically node-positive (cN+) HER2 + BC.
Methods: TRYPHAENA and NeoSphere are two randomized phase II trials that investigated PST for HER2 + BC. The current study is a pooled analysis of both trials, focusing on cN + patients treated with HER2-targeted PST followed by breast-conserving surgery. The primary goal is to describe patterns of RNI practicein this population and its impact on breast cancer recurrence-free survival (BCRFS) and loco-regional recurrence-free survival (LRRFS).
Results: Our analysis included a total of 90 patients with cN + disease. Complete nodal pathological response was achieved in 53 patients (58.9%). Patients with ypN0 had a 5-year LRRFS of 95.83% whereas patients with ypN + had 5-year LRRFS of 87.43% (p = 0.105). RNI was used in 16 ypN0 (48.5%) patients and 17 ypN+ (51.5%) patients. Patients treated with RNI had 5-year LRRFS of 93.4% as compared to 92.5% in the no RNI group (p = 0.868). Distant metastasis was detected in 5 patients (5%) with the most common sites being: liver, lung, bone, and CNS. Locoregional recurrence was significantly associated with distant failure (p = 0.002).
Conclusions: cN + HER2 + BC patients who achieve ypN0 after PST have excellent locoregional control. In contrast, patients with ypN + tend to have lower locoregional control. The utility of RNI in HER2 + BC warrants further investigation.
BMC Cancer , article en libre accès, 2025